Use libgit2 to filter working directory changes

For each changed path, discover the repository for that path and compare it to the repository that is open.  If they don't match, it's a submodule or another repo within the top-level one.  Either way, changes to that module shouldn't be committed to our repo (not that I offer any guarantee that GitX would do the expected commit correctly anyway…)

This fixes brotherbard#1 - although I'm yet to test the performance on a big repo with many files/submodules.

Author: rowanj

PBGitRepositoryWatcher.m

@@ -11,6 +11,8 @@
 #import "PBGitDefaults.h"
 #import "PBGitRepositoryWatcherEventPath.h"
 
+#import <ObjectiveGit/ObjectiveGit.h>
+
 NSString *PBGitRepositoryEventNotification = @"PBGitRepositoryModifiedNotification";
 NSString *kPBGitRepositoryEventTypeUserInfoKey = @"kPBGitRepositoryEventTypeUserInfoKey";
 NSString *kPBGitRepositoryEventPathsUserInfoKey = @"kPBGitRepositoryEventPathsUserInfoKey";
@@ -110,10 +112,22 @@ - (BOOL) _gitDirectoryChanged {
 
 - (void) _handleEventCallback:(NSArray *)eventPaths {
 	PBGitRepositoryWatcherEventType event = 0x0;
-
+	
 	if ([self _indexChanged])
 		event |= PBGitRepositoryWatcherEventTypeIndex;
 
+	NSString* ourRepo_ns = repository.fileURL.path;
+	// libgit2 API results for directories end with a '/'
+	if (![ourRepo_ns hasSuffix:@"/"])
+		ourRepo_ns = [NSString stringWithFormat:@"%@/", ourRepo_ns];
+	
+	const char* ourRepoPath = [ourRepo_ns UTF8String];
+	
+	// We only use the event path buffer for testing equality to our own repo
+	// so it's okay to consider failure due to buffer size as inequality.
+	const int eventPathRepoBufferSize = strlen(ourRepoPath) + 2;
+	char *eventPathRepoBuffer = malloc(eventPathRepoBufferSize);
+	
     NSMutableArray *paths = [NSMutableArray array];
 
 	for (PBGitRepositoryWatcherEventPath *eventPath in eventPaths) {
@@ -142,12 +156,22 @@ - (void) _handleEventCallback:(NSArray *)eventPaths {
 
 		// subdirs of working dir
 		else {
-			// Try to get the git status of the changed path using libgit2
-			if (![eventPath.path hasSuffix:@"/.git/"])
-			{
-				event |= PBGitRepositoryWatcherEventTypeWorkingDirectory;
-				[paths addObject:eventPath.path];
-			}
+			// check that the repo for the changed path is ours, otherwise
+			// it's most likely a submodule, or a nested clone.  Either way,
+			// we shouldn't be committing to it ourselves.
+
+		
+			int discoverStatus = git_repository_discover(eventPathRepoBuffer, eventPathRepoBufferSize,
+														 [eventPath.path UTF8String],
+														 1 /* cross filesystem boundaries, if necessary*/,
+														 ourRepoPath);
+			if (GIT_SUCCESS == discoverStatus &&
+				strcmp(ourRepoPath, eventPathRepoBuffer) == 0)
+				{
+					event |= PBGitRepositoryWatcherEventTypeWorkingDirectory;
+					[paths addObject:eventPath.path];
+				}
+//			}
 		}
 	}
 
@@ -160,6 +184,8 @@ - (void) _handleEventCallback:(NSArray *)eventPaths {
 
 		[[NSNotificationCenter defaultCenter] postNotificationName:PBGitRepositoryEventNotification object:repository userInfo:eventInfo];
 	}
+	
+	free(eventPathRepoBuffer);
 }
 
 - (void) start {